I have a couple of those, and yes that is actually a great idea. No need to re-invent the wheel.

I was referring til JTag, which by "google" it seems to be possible, but not recommended.

Glad you have it figured out, but I wanted to clarify this for others that may see this post.
There is nothing wrong at all programming it with JTAG.

Just trying to get a vibe on if creating a ESP32 Pocket Programmer would be a good venture or not. We have used these for many years on the production floor, and for infield updates for Atmel products. http://npe-inc.com/pocket-programmer/ Basically you upload your firmware to the programmer, connec...

but I have now read several places that this is not supported/recommended with ESP32.

Where did you see that ?

How about the ESP32 Programming Tool ?

If what Kolban says does not work, and your sure you have the right com port. Try sticking a 0.1uf -0.22uf from pin 3 (EN) to gnd.

Try sticking a 0.1uf -0.22uf from pin 3 (EN) to gnd.

That was measured with a scope with 4kHz signal. There's no negative voltage if I drop the GPIO drive strength to minimum. I would not expect a piezo transducer to work well if it's just in series with the drain of a transistor but that should be OK for the electro-magnetic transducer. Cool, at lea...

Just an FYI, it's not a good idea to drive a piezo electric device via a GPIO pin. Piezo devices can generate negative voltages. I'm getting only -40mV. Is that measured with a scope or meter. You will get much higher voltages than this when you turn a piezo off at the right time. Similar to say wh...

It would help if you provide a link to the type of buzzer you are using. It sounds to me as if it's probably a piezo transducer such as this. If so, drive it directly from a GPIO, not through a transistor. Just an FYI, it's not a good idea to drive a piezo electric device via a GPIO pin. Piezo devi...

ok, cool. what about "Did you look at the pin via a scope to ensure your getting the square wave output ?"